In a water cooled two cycle internal combustion engine, it is known to provide a bypass water valve which is closed at low or idle speeds of the engine to restrict the flow of water or coolant within the engine block and enable the engine to warm up. The water valve is typically spring biased to a normally closed condition. At higher engine speeds, the water pressure in the engine block overcomes the spring bias and opens the valve to enable the water to flow to another part of the cooling system such as a radiator.
Problems have been encountered at low engine speeds where the water pressure in the engine block may be high enough to overcome the valve spring force and thus open the valve and force water therethrough. This is undesirable because it does not allow the engine to warm up. The engine may not get hot enough, and hence the engine does not idle well and may require a richer fuel mixture which in turn creates more smoke. A higher spring pressure on the valve is not an acceptable solution because this would not allow the valve to open early enough at higher engine speeds, which in turn would cause the water pressure to be too high at the higher engine speeds and also would not afford the increased cooling necessary at the higher speeds.
The present invention addresses and solves the above noted problem without increased spring pressure and without complicated mechanical linkage.